DRP, a Twining Company, is a leader in concrete petrography. Established in 1999 and managed by David Rothstein, Ph.D., P.G., DRP is headquartered in Boulder, Colorado and uses the latest proven concrete petrography and other analytical methods to investigate concrete and other cement-based construction materials, natural rock products, and geological resources. Our work ranges from providing concrete quality assurance to diagnosing causes of deterioration. With extensive experience in concrete materials and early age problems, durability mechanisms, and the performance of slabs ranging from pavements to industrial floors, we help engineers formulate solutions that range from minor repairs to removal and replacement. Our expertise also includes investigations of fire damage, interior plaster and stucco failures, issues with lightweight concrete, swimming pool plasters and finishes, gunite and shotcrete, tile and terrazzo, dimension stone and cladding failures, cement-stabilized soils, lime-stabilized base materials and more. Our clients include facility owners, general contractors, concrete and specialty contractors, materials suppliers, consulting civil and structural engineers, academic researchers, insurance companies, state and municipal government agencies and legal firms.